JP2000058251A - Coil for induction heating and coil molding for induction heating - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a coil for induction heating and a coil mold for induction heating capable of remarkably reducing the production cost and stably holding the shape of the coil for a long time. SOLUTION: An insulated electric wire formed by stacking an insulating layer made of fluororesin having a melting point of T1 deg.C and a fused layer made of a thermoplastic resin having a melting point of T2 deg.C on a conductor in this order is spirally or cylindrically wound, then is fusion bonded in one body, and constituted with either one of polyester elastomer, a polyamide resin, and a polyurethane resin satisfying the condition of T1-T2<=100. A coil for induction heating is fusion-bonded to a polyester film, and by sticking and/or adhering the surface of the polyester film, where the coil for induction heating of the polyester film is not attached, an assembly capable of fixing is formed. A double-coated pressure sensitive adhesive tape is fit onto one side of the coil for induction heating, the an assembly capable of fixing is formed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an induction heating coil and an induction heating coil which can be suitably used as, for example, a coil for a lid heater or a coil for a body heater of an electric rice cooker utilizing an electromagnetic induction heating system. The present invention relates to a molded coil product.

[0002]

2. Description of the Related Art In recent years, electric rice cookers using an electromagnetic induction heating method have become widespread in ordinary households and the like.
A spiral wound polyester film on a fluororesin insulated wire having an insulating layer made of fluororesin formed on a conductor is used as a coil wire, and the coil wire is spirally wound. Temporarily fix multiple places with polyester tape with adhesive, etc., then arrange polyester film with adhesive on the upper surface, double-sided adhesive tape on the lower surface, respectively, and bond them together for induction heating. A coil is arranged. Also, as in the case of the above-described lid heater coil, a fluororesin insulated wire having a polyester film wound on its surface is used as a coil wire, as in the case of the above-described lid heater coil, on the outer peripheral side surface of the inner pot of the electric rice cooker. After use, the coil wire is wound in a cylindrical shape, and an induction heating coil having a configuration in which a plurality of portions are fixed with a polyester tape or the like with an adhesive is disposed.

[0003] The reason why the polyester film is wound on the insulated wire is that the fluororesin constituting the insulating layer is difficult to adhere to other substances. This is because it is possible to adhere to a polyester tape, a polyester film, a double-sided pressure-sensitive adhesive tape or the like, and to keep the shape of the coil in a good condition.

In this type of induction heating coil, since a fluororesin insulated wire used as a coil wire has excellent heat resistance, a coil for a lid heater or a coil for a body heater of an electric rice cooker is used. Besides, it can be used as a heater coil of various induction heating cookers.

[0005]

However, the conventional induction heating coil has the following problems. First, in the case of an induction heating coil used as a lid heater coil, the manufacturing process is a process of winding a polyester film on a fluororesin insulated wire,
Numerous manufacturing processes, such as temporarily fixing fluororesin insulated wires using a polyester tape with adhesive, and bonding and integrating with fluororesin insulated wires using a polyester film with adhesive and double-sided adhesive tape Therefore, the working efficiency is very poor and the productivity is inferior, and the number of parts increases, so that the manufacturing cost increases. In addition, in the case of the induction heating coil used as the body heater coil, the configuration is such that the coil wire wound in a cylindrical shape is only partially fixed with a polyester tape or the like with an adhesive. There is a drawback that the shape of the coil easily collapses if care is not taken when mounting it inside.

In order to solve such a problem, for example, the fluororesin insulated wires are fused and integrated by heating, or a fusion layer made of a thermoplastic resin is formed on the circumference of the fluororesin insulated wire. As a countermeasure, it is possible to fuse and integrate the fusion layers.

However, first, when the fluororesin insulated wires are fused and integrated, the fluororesin insulating layer is usually formed to a thickness of about 0.15 mm. However, there is a drawback that the metal is deformed and the insulation performance is reduced.

In the case where the fusion layers formed on the periphery of the fluororesin insulated wire are fused and integrated, for example, a thermoplastic resin constituting the fusion layer is generally used in various fields. When using polyolefin resins or hot melt adhesives that have been used, the melting point of these resins is at most about 120 ° C, so the usable temperature range becomes very narrow, and the heat resistance as a coil strand is reduced. The advantage of using an excellent fluororesin insulated wire is lost.

The present invention has been made on the basis of the above points, and the object thereof is to simplify the manufacturing process and reduce the number of parts, so that the manufacturing cost can be greatly reduced and the long-term stability can be maintained. Induction heating coil and induction heating coil molded product suitable for use as, for example, a lid heater coil or a body heater coil of an electric rice cooker using an electromagnetic induction heating method, which can maintain the shape of the coil Is to provide.

[0010]

In order to achieve the above-mentioned object, an induction heating coil according to the present invention has a melting point T ₁ on a conductor.
An insulated wire formed by sequentially forming an insulation layer made of a fluororesin having a melting point of ₂ ° C. and a fusion layer made of a thermoplastic resin having a melting point of T ₂ ° C.
An induction heating coil formed by spirally winding the insulated wires and fusing and integrating the insulated wires, wherein the thermoplastic resin is T ₁ −
It is characterized by being composed of any one of a polyester elastomer, a polyamide resin and a polyurethane resin satisfying a condition of T ₂ ≦ 100.

According to another aspect of the present invention, there is provided an induction heating coil molded product, wherein the induction heating coil is fused to a polyester film, and the side of the polyester film on which the induction heating coil is not provided. The assembly can be mounted by an adhesive process and / or an adhesive process on the surface.

[0012] Further, in the induction heating coil molded product according to another aspect of the present invention, a double-sided adhesive tape having a total area equal to or smaller than the horizontal projected area of the coil is mounted on one surface of the induction heating coil. And an attachable assembly.

At this time, it is conceivable that the double-sided pressure-sensitive adhesive tape is cut into small pieces and is attached to a plurality of locations on one side of the induction heating coil.

According to another aspect of the present invention, there is provided an induction heating coil in which an insulating layer made of a fluororesin having a melting point of T ₁ ° C and a fusion layer made of a thermoplastic resin having a melting point of T ₂ ° C are sequentially formed on a conductor. An insulated wire obtained by winding an insulated wire having a cylindrical shape and then fusing and integrating the insulated wire,
The thermoplastic resin is characterized by being composed of any one of a polyester elastomer, a polyamide resin and a polyurethane resin satisfying a condition of T ₁ −T ₂ ≦ 100.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION An insulated wire used as a coil wire in the present invention is one in which an insulating layer made of a fluororesin and a fusion layer made of a thermoplastic resin are sequentially formed on a conductor. As the fluororesin constituting the insulating layer, for example, ethylene tetrafluoride-propylene hexafluoride copolymer (FEP), ethylene-tetrafluoroethylene copolymer (E
TFE) and ethylene tetrafluoride-perfluoroalkyl vinyl ether copolymer (PFA).
Any of these fluororesins may be used,
In consideration of cost reduction, it is preferable to use ethylene tetrafluoride-propylene hexafluoride copolymer (FEP) or ethylene-tetrafluoroethylene copolymer (ETFE).

As the thermoplastic resin constituting the fusion layer,
When the melting point of the fluororesin used is T ₁ ° C. and the melting point of the thermoplastic resin is T ₂ ° C., preferably, T ₁ −T ₂ ≦ 10.
0, and more preferably, any one of a polyester elastomer, a polyamide resin and a polyurethane resin satisfying the condition of 50 ≦ T ₁ −T ₂ ≦ 100 is used. T ₁ -T
_If the value of ₂ exceeds 100, the excellent heat resistance of the fluororesin insulated wire cannot be utilized, which is not preferable. Also, the value of T ₁ -T ₂ is 50
When less than one is used, when the fusion layers are fused and integrated by heating, a method of heating and fusing the fusion layer by resistance heat generated by flowing an electric current to the conductor is employed as a means thereof. In such a case, the fluororesin may be softened and deformed by the influence of the heat, which is not preferable.

In the present invention, the insulated wire having the above structure is wound in a spiral or cylindrical shape, and then the insulated wire is fused and integrated to form an induction heating coil. As means for fusing and integrating the insulated wires, any conventionally known method can be adopted, and there is no particular limitation. For example,
A method in which an insulated wire wound in a spiral or cylindrical shape is left in a bath maintained at a predetermined temperature for a predetermined time to be integrated by heating and fusion, or as described above, a predetermined For example, a method in which the fusion layer is heated and melted from the inside by resistance heat generated by flowing the current, and integrated.

Further, the spiral induction heating coil obtained as described above is further fused to a polyester film,
If the surface of the polyester film on which the induction heating coil is not provided is appropriately subjected to an adhesive process and / or an adhesive process, the induction heating coil molded product can be easily attached to various devices. can do.

If a double-sided adhesive tape having a total area equal to or smaller than the horizontal projection area of the coil is attached to one side of the spiral induction heating coil obtained as described above, various types of equipment can be provided. And a coil molded product for induction heating that can be easily mounted on the coil.

Examples of the double-sided adhesive tape include Japanese paper,
Paper materials such as kraft paper, fiber materials such as glass fiber and nonwoven fabric,
Films, tapes or sheets made of organic polymer materials such as polyethylene terephthalate, polyethylene naphthalate, polyimide, polyphenylene sulfide, polyetheretherketone, polyetherimide, polyethersulfone, polyarylate, polycarbonate, silicone rubber, and fluororesin, ceramics A tape or sheet made of an inorganic material such as mica as a support,
Acrylic-based, epoxy-based, polyester-based, polyurethane-based, silicone-based, polyimide-based, fluorine-based, and ceramic-based adhesives or adhesive layers formed of an adhesive are formed on the upper and lower surfaces of the support. . Although any of these may be used, it is preferable to use a nonwoven fabric having excellent flexibility as a support in consideration of the use situation.

Form of double-sided adhesive tape (size, shape, etc.)
As described above, a form in which the total area of the tape is equal to or smaller than the horizontal projection area of the induction heating coil, preferably, the total area of the double-sided adhesive tape with respect to the horizontal projection area of the induction heating coil The ratio is 0.
Any form can be used as long as it is in the range of 03 to 1.0. For example, a donut punched out according to the shape of the induction heating coil is attached to one side of the coil, or a small piece such as a circle, triangle, square, or pentagon is cut and attached to a plurality of locations on one side of the coil. And so on. Here, if the total area ratio of the double-sided pressure-sensitive adhesive tape to the horizontal projection area of the induction heating coil is less than 0.03, it becomes difficult to attach it to various devices. However, the material loss of the double-sided adhesive tape increases. Of course, the total area ratio of the double-sided adhesive tape to the horizontal projection area of the induction heating coil is 1.
Even in the case of 0, for example, when the shape of the double-sided pressure-sensitive adhesive tape is a donut shape as described above, the circular portion at the center becomes a material loss at the time of punching and molding. In consideration of cost reduction due to dramatic reduction, it is desirable to use a double-sided adhesive tape cut into small pieces.

[0022]

Embodiments of the present invention will be described below. The induction heating coil molded products described as Examples 1 to 6 and Comparative Example 1 were manufactured on the assumption that they were applied to a lid heater coil of an electric rice cooker using an electromagnetic induction heating method. The induction heating coil described as Example 7 and Comparative Example 2 is manufactured assuming that it is applied to a body heater coil of an electric rice cooker using an electromagnetic induction heating method. It is an example.

Example 1 In this example, a coil molded product for induction heating was manufactured by the following procedure. First, an induction heating coil was manufactured as follows. On a conductor having an outer diameter of 0.9 mm obtained by twisting 19 tin-plated annealed copper wires having a strand diameter of 0.18 mm, a tetrafluoroethylene-propylene hexafluoride copolymer (FEP) having a melting point T _{1 of} 265 ° C. After forming an insulating layer by extrusion coating with a thickness of 0.125 mm, a polyester elastomer having a melting point T ₂ : 182 ° C. of 0.03 ° C. was further formed on the insulating layer.
It was extrusion-coated with a thickness of 2 mm to form a fused layer, and an insulated wire having a finished outer diameter of 1.2 mm was obtained. At this time, the value of T ₁ -T ₂ was 83 ° C., which satisfied the range of the present invention. Next, the insulated wire is spirally wound so as to have an inner diameter of 133 mm and an outer diameter of 169 mm.
A current of 30 A was passed through the insulated wires for 30 seconds to cause the conductor to self-heat, and the heat melted the fusion layer made of the polyester elastomer to fuse and integrate the insulated wires.

Next, the induction heating coil obtained as described above was provided with an adhesive material and release paper on one side,
8 mm, an outer diameter of 184 mm is placed on a surface of a polyester film punched and formed into a donut shape on which no adhesive material is provided, and a predetermined pressure is applied to the insulated wire constituting the induction heating coil in a state of 30 A. An electric current was passed for 30 seconds to cause the conductor to self-heat, and the heat melted the fusion layer made of the polyester elastomer, which was fused and integrated with the polyester film to obtain a coil molded product for induction heating.

Example 2 A coil molded product for induction heating was manufactured by using the same material and the same method as in Example 1 except that a polyester elastomer having a melting point of 172 ° C. was used as the polyester elastomer constituting the fused layer. At this time, the value of T ₁ -T ₂ was 93 ° C., which satisfied the range of the present invention.

Comparative Example 1 A coil molded product for induction heating was manufactured by using the same material and the same method as in Example 1 except that a polyester elastomer having a melting point of 154 ° C. was used as the polyester elastomer constituting the fused layer. At this time, the value of T ₁ -T ₂ is 111 ° C., which exceeds the upper limit (100 ° C.) of the range of the present invention.

Example 3 First, as the thermoplastic resin constituting the fusion layer, a melting point of 18 was used.
Except for using a polyamide resin at 0 ° C., a coil for induction heating was manufactured by the same material and the same method as in Example 1. At this time, the value of T ₁ -T ₂ was 85 ° C., which satisfied the range of the present invention.

Next, on one side of the induction heating coil obtained as described above, a double-sided adhesive tape (a horizontal projection area of the induction heating coil: double-sided) formed by punching and forming a donut having an inner diameter of 133 mm and an outer diameter of 169 mm. Adhesive tape area =
1: 1) to obtain a molded coil for induction heating. As the double-sided pressure-sensitive adhesive tape, one having a non-woven fabric as a support, and an adhesive layer made of an acrylic pressure-sensitive adhesive formed on both upper and lower surfaces thereof was used. In addition, this double-sided adhesive tape is 200 mm
133mm inside diameter, 1 outside diameter from square shape of × 200mm
Since it was punched and formed into a doughnut shape of 69 mm, a hollow portion having a diameter of 133 mm or the like was a material loss.

Example 4 First, as the thermoplastic resin constituting the fusion layer, a melting point of 17 was used.
Except for using a polyurethane resin at 7 ° C., a coil for induction heating was manufactured by the same material and the same method as in Example 1. At this time, the value of T ₁ -T ₂ was 88 ° C., which satisfied the range of the present invention.

Next, on one surface of the induction heating coil obtained as described above, four double-sided adhesive tapes cut into a rectangular shape of 25 mm × 16 mm (horizontal projection area of the induction heating coil: double-sided adhesive tape) Total area = 1: 0.1
4) was mounted diagonally to obtain a coil molded product for induction heating. As the double-sided pressure-sensitive adhesive tape, as in the case of Example 3, a non-woven fabric was used as a support, and an adhesive layer formed of an acrylic pressure-sensitive adhesive was formed on both upper and lower surfaces.
In addition, since this double-sided pressure-sensitive adhesive tape was 96 pieces of a rectangular shape of 200 mm × 192 mm to a rectangular shape of 25 mm × 16 mm, no material loss occurred.

Example 5 A double-sided pressure-sensitive adhesive tape punched and formed into a donut shape having an inner diameter of 133 mm and an outer diameter of 169 mm (horizontal side of the induction heating coil) was formed on one surface of an induction heating coil having the same configuration as that used in Example 1. Projected area: area of double-sided adhesive tape = 1:
1) was mounted to obtain a coil molded product for induction heating. As the double-sided pressure-sensitive adhesive tape, one having a non-woven fabric as a support, and an adhesive layer made of an acrylic pressure-sensitive adhesive formed on both upper and lower surfaces thereof was used. In addition, this double-sided adhesive tape is 200 mm × 2
133mm inside diameter, 169 outside diameter from 00mm square shape
As a result, the circular portion having a diameter of 133 mm, which had been hollowed out, resulted in material loss.

Example 6 On one surface of an induction heating coil having the same structure as that used in Example 1, four double-sided adhesive tapes cut into a rectangular shape of 25 mm × 16 mm (horizontal projection area of the induction heating coil) : Total area of double-sided pressure-sensitive adhesive tape = 1: 0.14) was mounted on a diagonal line to obtain a coil molded product for induction heating. As the double-sided pressure-sensitive adhesive tape, a tape having a non-woven fabric as a support and a pressure-sensitive adhesive layer made of an acrylic pressure-sensitive adhesive formed on both upper and lower surfaces was used in the same manner as in Example 5. In addition, this double-sided pressure-sensitive adhesive tape has a rectangular shape of 200 mm × 192 mm to a rectangular shape of 25 mm × 16 mm.
No material loss occurred due to individual cutting.

Example 7 An induction heating coil was manufactured according to the following procedure. First,
An ethylene-tetrafluoroethylene copolymer (ETFE) having a melting point T _{1 of} 267 ° C. was added to a conductor having an outer diameter of 0.9 mm obtained by twisting 19 tin-plated soft copper wires having a wire diameter of 0.18 mm.
After extrusion coating with a thickness of 125 mm to form an insulating layer,
Further, on the periphery thereof, a polyester elastomer having a melting point T _{2 of} 182 ° C. was extrusion-coated with a thickness of 0.03 mm to form a fused layer, and an insulated wire having a finished outer diameter of 1.2 mm was obtained. At this time, the value of T ₁ -T ₂ was 85 ° C., which satisfied the range of the present invention. Next, this insulated wire was 234 mm in inner diameter,
The conductor is wound in a cylindrical shape so as to have a height of 8.5 mm, and while maintaining that state, a current of 30 A is passed through the insulated wire for 20 seconds to cause the conductor to generate heat. By melting, the insulated wires were fused and integrated.

Comparative Example 2 An induction heating coil was manufactured by using the same material and the same method as in Example 7 except that a polyester elastomer having a melting point of 154 ° C. was used as the polyester elastomer constituting the fused layer. At this time, the value of T ₁ -T ₂ is 113 ° C., which exceeds the upper limit (100 ° C.) of the range of the present invention.

The following tests were carried out using the nine types of induction heating coil molded products and induction heating coils thus obtained as samples.

Each sample was left in a thermostat maintained at 180 ° C. for 3 hours and then taken out, and the appearance of the coil was visually checked.

As a result, no abnormalities were found in the coils of Examples 1 to 7, but the coils of Comparative Examples 1 and 2 were insulated from each other because the fusion layer was melted and deformed. Were separated, and the shape of the coil was not maintained.

In this embodiment, the following tests were further performed using the coil-formed products for induction heating shown in Embodiments 1 to 6 as samples.

Each sample was mounted on the lid of an electric rice cooker, and
After leaving for 1 hour in a thermostat kept at 5 ° C., it is immediately transferred to a thermostat kept at 135 ° C. and left for 1 hour.
After 100 cycles of such a cooling / heating cycle test, the appearance of the coil and the state of attachment to the lid were visually checked.

As a result, no abnormalities such as separation of the insulated wires of the coil and dropping from the lid of the electric rice cooker were observed in any of the coil molded products of Examples 1 to 6.

[0041]

As described above in detail, according to the present invention, an insulating layer of a fluororesin having excellent heat resistance is formed on a conductor, and a thermoplastic resin (polyester elastomer, polyamide resin or polyurethane) having a specific range of melting point. By using an insulated wire having a structure in which a fusion layer of (resin) is sequentially formed as a coil element wire, an induction heating coil and a molded product for induction heating coil can be obtained with a simple manufacturing process and a small number of components. Therefore, the manufacturing cost can be reduced. Therefore, it can be used in a wide range of applications by fully utilizing the characteristics of the fluororesin insulated wire having excellent heat resistance.

Claims (5)

[Claims] 1. An insulated wire in which an insulating layer made of a fluororesin having a melting point of T ₁ ° C. and a fusion layer made of a thermoplastic resin having a melting point of T ₂ ° C. are sequentially formed on a conductor, and then spirally wound. ,
An induction heating coil formed by fusing and integrating the insulated wires, wherein the thermoplastic resin is made of any one of a polyester elastomer, a polyamide resin, and a polyurethane resin satisfying a condition of T ₁ -T ₂ ≦ 100. A coil for induction heating. 2. The induction heating coil according to claim 1, wherein the induction heating coil is fused to a polyester film, and the side of the polyester film on which the induction heating coil is not provided is subjected to an adhesion process and / or an adhesion process. A coil molded product for induction heating, which is an assembly that can be mounted. 3. A double-sided pressure-sensitive adhesive tape having a total area equal to or smaller than a horizontal projection area of the coil is mounted on one surface of the induction heating coil according to claim 1, and is a mountable assembly. A coil molded product for induction heating, characterized in that: 4. The induction heating coil molded product according to claim 3, wherein the double-sided pressure-sensitive adhesive tape is cut into small pieces and attached to a plurality of locations on one surface of the induction heating coil. Coil molding for induction heating. 5. After winding an insulated wire in which an insulating layer made of a fluororesin having a melting point T ₁ ° C. and a fusion layer made of a thermoplastic resin having a melting point T ₂ ° C. are sequentially formed on a conductor, the insulated wire is wound into a cylindrical shape. ,
An induction heating coil formed by fusing and integrating the insulated wires, wherein the thermoplastic resin is made of any one of a polyester elastomer, a polyamide resin, and a polyurethane resin satisfying a condition of T ₁ -T ₂ ≦ 100. A coil for induction heating.